If your question,is that legal to another Muslim to be a guardian for Muslim woman in marrage contact? , the answer is: that not permissible, except in case, that her legitimate guardians are non-Muslims, and
Please be aware. if her father is muslim and alive and she can connect him, it is not permissible for any of her brothers or others to be guardian,but if her walis non-Muslims then, she can choose good muslim man except her husband to be a Wali for her in marrage contact.
Allah knows best

If your question,is that legal to another Muslim to be a guardian for Muslim woman in marrage contact? , the answer is: that not permissible, except in case, that her legitimate guardians are non-Muslims, and Please be aware. if her father is muslim and alive and she can connect him, it is not permissible for any of her brothers or others to be guardian,but if her walis non-Muslims then, she can choose good muslim man except her husband to be a Wali for her in marrage contact. Allah knows best